Pharmacotherapy of



Pharmacological Treatment Options for HYPOTHYROIDISM

Ian Baker, PharmD Candidate 2007

| |Therapeutic Class/Agents |Therapeutic Class/Agents |Therapeutic Class/Agents |Therapeutic Class/Agents |

| |Synthetic Thyroid Hormone | | | |

|Product Availability |Generic/Brand | | | |

|Generic (Brand) |Levothyroxine/(Levothroid, Levoxine, Levoxyl, Synthroid, Unithroid) | | | |

| |Liothyronine /(Cytomel, Triostat) | | | |

| |Liotrix /(Thyrolar) (*not used often due to price and mechanism of action) | | | |

| |Thyroid Dessicated/ (Armour Thyroid) (*not commonly used due to better safety profile and | | | |

| |predictability with synthetic formulations) | | | |

|Mechanism | | | | |

|of Action |*These medications are synthetic and natural T3 and T4 substitutes, and are used to maintain TH | | | |

| |levels in patients with hypothyroidism. | | | |

| | | | | |

| |Levothyroxine is a synthetic T4 substitute | | | |

| |Liothyronine is a synthetic T3 substitute | | | |

| |Liotrix and thyroid dessicated are T3/T4 combined. Dessicated is a natural pork derivative. | | | |

|EFFICACY | | | | |

| |All preparations are equally effective, but may differ in bioavailability which is why it is | | | |

|(Indication/Use, |important to only use one brand. | | | |

|Clinical Data Support) |Onset of action can take several weeks | | | |

| | | | | |

| | | | | |

| | | | | |

| |*Mandel SJ. Brent GA. Larsen PR. Levothyroxine therapy in patients with thyroid disease. Annals | | | |

| |of Internal Medicine. 119(6):492-502, 1993 Sep 15. | | | |

| | | | | |

| |*Dong BJ. Hauck WW. Gambertoglio JG. Gee L. White JR. Bubp JL. Greenspan FS. Bioequivalence of | | | |

| |generic and brand-name levothyroxine products in the treatment of hypothyroidism. JAMA. | | | |

| |277(15):1205-13, 1997 Apr 16. | | | |

|SAFETY |Black Box Warning | | | |

| |Hypothyroid drugs should never be used for weight loss. The doses required to lose weight are | | | |

|(Major Drug |high and can be fatal. | | | |

|Interactions, | | | | |

|Pre-cautions, |Contraindicated in patients with: | | | |

|Contra-indications, |acute MI | | | |

|Adverse Effects, |uncorrectedAdrenal insufficiency | | | |

|Pregnancy Risk Category)|hypersensitivity to any of the drug components | | | |

| | | | | |

| | | | | |

| |Side effects that you should report to your prescriber or health care professional as soon as | | | |

| |possible: | | | |

| |•difficulty breathing, wheezing, or shortness of breath | | | |

| |•chest pain | | | |

| |•excessive sweating or intolerance to heat | | | |

| |•fast or irregular heartbeat or pulse rate | | | |

| |•nervousness | | | |

| |•skin rash or hives | | | |

| |•swelling of ankles, feet or legs | | | |

| | | | | |

| |Pregnancy Category: A | | | |

| |Therapeutic Class/Agents |Therapeutic Class/Agents |Therapeutic Class/Agents |Therapeutic Class/Agents |

|Dosage & Administration | | | | |

| |Levothyroxine | | | |

|(Include renal and/or |Start: 12.5-50mcg PO qd; adjust dose by 12.5mcg-25mcg/day q4-8wk based on TFTs; Max: 300mcg/day. | | | |

|hepatic adjustments) |If given IM/IV give 50% of PO dose. | | | |

| | | | | |

| |Liothyronin | | | |

| |Cytomel (Tablet): 25-75mcg PO qd; start 25mcg PO qd, incr. 12.5-25mcg q1-2wk | | | |

| |Triostat (IV): 25-50mcg IV X1; reassess after 4-12h, witch to PO as soon as possible | | | |

| | | | | |

| |Liotrix | | | |

| |Composition | | | |

| |(T3/T4 per tablet in mcg) | | | |

| |Start: one tablet of Thyrolar 6.25/25 ; adjusts dose to one tablet of Thyrolar 3.1/12.5 every 2 | | | |

| |to 3 weeks | | | |

| | | | | |

|Monitoring | | | | |

| |These medications have a long half-life, so TSH, T3 and T4 levels should be taken 4-6weeks after | | | |

|(Efficacy and Toxicity |first dose | | | |

|Parameters) |Adjusted every 6-8 weeks until levels are normalized. | | | |

| |Once normalized, test biochemically every 6-12months. | | | |

| | | | | |

| |Efficacy: | | | |

| |Resolution of signs and symptoms (see above) | | | |

| |TSH levels | | | |

| |Toxicity: | | | |

| |Irregular heart beat/Chest pain | | | |

| |Tremors | | | |

| |SOB | | | |

| |Diarrhea/Nausea/Vomitting | | | |

| |Weight gain/Weight loss | | | |

| | | | | |

|Patient Education |Take medication only as directed by your doctor | | | |

| |Do not switch brands of medication unless your prescriber agrees with the change. | | | |

| |It may be necessary for you to take this medicine for the rest of your life. | | | |

| |You may lose some of your hair while using levothyroxine. With time, this usually corrects itself.| | | |

| |Be sure to take your levothyroxine tablets with a full glass of water. | | | |

| |Take levothyroxine tablets by mouth 30—60 minutes before a meal (on an empty stomach) first thing | | | |

| |in the morning | | | |

| |Keep all doctor appointments | | | |

| | | | | |

|Cost | | | | |

|(1-month) |Levothyroxine (generic) | | | |

| |25mcg-88mcg (30 ea): $8.99 | | | |

| |100mcg, 112mcg (30ea): $9.99 | | | |

| |125mcg, 137mcg, 150mcg (30ea): $10.99 | | | |

| |175mcg, 200mcg, 300mcg (30ea): $11.99 | | | |

| | | | | |

| |Liothyronin (1 month supply is highly variable per patient, so cost does not reflect 1month | | | |

| |supply) | | | |

| |Cytomel (liothyronin tablet) | | | |

| |5mcg (100ea): $69.40 | | | |

| |25mcg (100ea): $89.99 | | | |

| |50mcg (100ea): $135.53 | | | |

| |Triostat (liothyronin IV) | | | |

| |Liotrix | | | |

| |15mg (30ea):$17.62 | | | |

| |30mg (30ea):$19.70 | | | |

| |60mg (30ea):$23.87 | | | |

| |120mg (30ea):$28.03 | | | |

| |180mg (30ea) :$33.23 | | | |

|References |Drugdex | | | |

|(Guidelines, Drug Info |Epocrates | | | |

|Sources) |Lexicomp | | | |

| |Micromedex | | | |

| |Depiro 6th edition | | | |

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